Insights Into Epiretinal Membranes: Presence of Ectopic Inner Foveal Layers and a New Optical Coherence Tomography Staging Scheme

To describe the presence of continuous ectopic inner foveal layers associated with epiretinal membranes (ERMs) and to present a new optical coherence tomography (OCT) staging system of ERMs.Retrospective multicenter observational case series.Clinical charts and spectral-domain OCT images of 194 eyes of 172 consecutive patients diagnosed with ERMs were reviewed and analyzed.The presence of continuous ectopic inner foveal layers was identified in 63 out of 194 eyes (32.5%) and this morphology was significantly associated with lower visual acuity. ERMs were divided into 4 stages. Stage 1 (43 out of 194 eyes, 22.1%) ERMs were mild and thin and a foveal depression was present. Stage 2 (88 out of 194 eyes, 45.4%) ERMs were associated with widening of the outer nuclear layer and loss of the foveal depression. Stage 3 (51 out of 194 eyes, 26.3%) ERMs were associated with continuous ectopic inner foveal layers crossing the entire foveal area. In stages 1, 2, and 3 all retinal layers were clearly defined on OCT. Stage 4 ERMs (12 out of 194 eyes, 6.2%) were thick and associated with continuous ectopic inner foveal layers. In addition, retinal layers were disrupted. Visual acuity progressively declined from stage 1 through stage 4 (P < .001).The presence of continuous ectopic inner foveal layers in ERMs is a newly described OCT finding associated with significant vision loss and is an essential element of a novel OCT-based grading scheme of ERMs that may influence visual prognosis.